Please, I need your expertise!!

[SPOOLFOOL2]

You say that it does it at idle and at cruse. Does it clean up while accelerating? Or does it also do it under a load?
"Most" ignition issues get worse with more load.

Module?

 

[GN18944]

You say that it does it at idle and at cruse. Does it clean up while accelerating? Or does it also do it under a load?
"Most" ignition issues get worse with more load.

Module?

It cleans up perfect as soon as you dip into the throttle. This was why I was pursuing vacuum related issues to start with because when vacuum closes it runs perfect.

 

[Chuck Leeper]

because when vacuum closes it runs perfect.

Huh??
Some Scanmaster info available?

 

[GN18944]

Huh??
Some Scanmaster info available?

02's in the mid 700's
L8 37-39
Int 128
BL 126
Ats 68
TPS .44
IAC 24
cc 121

 

[GN18944]

Any new thoughts?

 

[gusszgs]

original TPS? Maybe worn in the two common positions? Just a thought

 

[TurboBuRick]

Stock maf? Translator?

Reset the chip then go for a good 10-15 minute drive then retake the scnmaster numbers.

 

[GN18944]

Stock maf? Translator?

Reset the chip then go for a good 10-15 minute drive then retake the scnmaster numbers.

Stock MAF - how do I reset the chip? This is interesting to me.

 

[GN18944]

original TPS? Maybe worn in the two common positions? Just a thought

It is the original TPS - Where are the usual wear spots? It looks okay to me. It does hold a steady TPS at idle according to the scanmaster

 

[GN18944]

Stock MAF - how do I reset the chip? This is interesting to me.

nevermind, found out how to do so.

 

[GN18944]

Stock maf? Translator?

Reset the chip then go for a good 10-15 minute drive then retake the scnmaster numbers.

Just finished driving the car as you suggested, here is the info from the scanmaster. I drove the car very lightly. After resetting the chip, prior to the drive it seemed to be running a bit better, after the drive it was business as usual with an inconsistent miss.

02's in the upper 500's
AF - 06
L8 - 40
Int - 128
BL - 127
ATS - 63
TPS - .44
IAC - 28

 

[GN18944]

Here are some information I have learned in the last 24 hours:
The car has a remanufactured ECU - interesting but probably means nothing
There have been a few MINOR changes to the car since the chip was burned... I run higher octane fuel and 3psi more than the chip was tuned for. I don't think this would cause a light throttle/idle miss, could it??

 

[Steve]

I had a similar problem with a GN I had years ago and it turned out that the rear hold down bolt was missing from the coilpack. I doubt you have the exact bolt missing but it could be a similar grounding issue that the missing bolt caused on my car. The car ran very well other than an occiasional miss at cruise.

 

[gusszgs]

It is the original TPS - Where are the usual wear spots? It looks okay to me. It does hold a steady TPS at idle according to the scanmaster

Cruise and idle positions are the most common areas of wear during the TPS lifespan. I was just thinking if it gets worn in those areas, it may lead to the type of issue you describe. Intermittent signal

 

[GN18944]

I had a similar problem with a GN I had years ago and it turned out that the rear hold down bolt was missing from the coilpack. I doubt you have the exact bolt missing but it could be a similar grounding issue that the missing bolt caused on my car. The car ran very well other than an occiasional miss at cruise.

I checked my grounds this evening and everything seems fine. I was almost hoping I would that the bolt was missing! haha

 

[GN18944]

Cruise and idle positions are the most common areas of wear during the TPS lifespan. I was just thinking if it gets worn in those areas, it may lead to the type of issue you describe. Intermittent signal

This is interesting to me especially since it's a common sensor to be moved during tuning process' over the years. Is there any way to prove this?

 

[GN18944]

Just a general update. I plan to check my cam sensor alignment this weekend when I have a few hours to dig into it. I also have a fresh chip coming from TT with all the current information in it since timing could also be an issue here.

 

[gusszgs]

I'm not sure, but I remember reading yrs ago about someone who had a miss at a certain throttle position and I believe the TPS was culprit. Your post made me think of this. Maybe you could try watching the SM with key on engine not running and look at your volts throughout the range numerous times. Or try another used if available.
Maybe someone else more knowledgeable than I knows how you could test it

 

[GN18944]

I'm not sure, but I remember reading yrs ago about someone who had a miss at a certain throttle position and I believe the TPS was culprit. Your post made me think of this. Maybe you could try watching the SM with key on engine not running and look at your volts throughout the range numerous times. Or try another used if available.
Maybe someone else more knowledgeable than I knows how you could test it

Understood. I'm out in the garage right now trying all kinds of basic diagnostic unplug things and see if it changes haha. Tried unplugging MAF with no change - tried unplugging TPS with no change.

 

[GN18944]

Two more quick pieces of info - hopefully by the end of the weekend I will have both a new Caspers cam sensor cap - the wiring looks like it may be weak inside the insultation and the price was right so I ordered one. I also have a new TT chip with all the right mods on it's way as well. Both shipped today. Still leaning toward timing here.